McConnell raised $2.3 million during that same period, which his campaign said was his strongest fundraising quarter ever. The incumbent now has $10 million cash on hand, while Lundergan Grimes has nearly $2 million cash in the bank.

The Kentucky Senate race is Democrats' best hope for a 2014 pickup, and her third quarter tally demonstrates the extent to which she is already benefitting from the Democrats' national fundraising muscle.

Lundergan Grimes, Kentucky's secretary of State, received contributions from more than 13,000 individual donors, more than double the nearly 6,000 that contributed to McConnell.

More than 11,000 of those individual donations came in amounts of $50 or less, which the campaign said was evidence of a "solid grassroots foundation" for her Senate bid. She received contributions from all 120 Kentucky counties and all 50 states.

Campaign adviser Jonathan Hurst said the haul reflects the fact that voters are fed up with McConnell.

“The record-breaking showing speaks to the overwhelming grassroots momentum behind Alison’s campaign and the fact that people across the political spectrum are tired of Mitch McConnell’s out-of-touch, failed leadership. Simply put, McConnell is not receiving a passing grade from Kentucky or this nation,” he said in a statement.